Speed controlling mechanism for



June 13, 1950 E. TELBIZOFF SPEED CONTROLLING uscmmsu FOR REVOLVING nouns Filed Feb.

Patented June 13, 1950 UNITED STATES PATENT OFFICE SPEED CONTROLLING MECHANISM FOR REVOLVING DOORS 8 Claims.

This invention relates to speed controlling mechanism for a revolving door, and more particularly to mechanism for limiting the speed of a revolving door to a predetermined maximum.

Rapid movement of revolving doors is hazardous and likely to produce personal injury. Whether the rapid movement be caused by a person passing through in a hurry or is deliberately produced as a prank, there is danger that the person next entering the door will be struck. Also, when a person passing through on one side gives the door a, rapid motion, there is great danger that the person passing through on the other side will get bumped by the door, resulting possibly in a foot or head injury.

One way of minimizing the danger is to mount the doors in tight engagement so that considerable force will be necessary to move the door and a great deal of eiiort would have to be expanded to make the door move at a rapid rate. This expedient, though it may minimize the danger somewhat, is unsatisfactory because it makes the door difiicult to operate so that children and others having lesser physical strength may pass through only with great difficulty or must require assistance to operate the door.

It is an important object of this invention to provide mechanism which will limit the speed of a revolving door without affecting the operation of the door at normal speeds and thus permit easy turning of the door at lower speeds but make it very difflcult to move the door at above a certain predetermined speed.

More specifically, it is an object of the invention to provide hydraulic braking mechanism electrically controlled and sensitive to the speed of the door for restricting movement of the door at high speeds. Other specific objects and advantages of the invention will appear as the speciflcation proceeds.

One embodiment of the invention is illustrated in the accompanying drawing in which Fig. 1 is a perspective view of a revolving door showing, in a schematic manner, the control mechanism which is associated with the door; Fig. 2 is a sectional view of the governor, the view being taken along the line 2-2 of Fig. 3; and Fig. 3 is a vertical sectional view of the governor, the section being taken along line 3-3 of Fig. 2, this view showing the electrical switch with which the governor cooperates.

The revolving doorA, as illustrated in Fig. 1, has a central vertical shaft Ill which at its bottom end is adapted to be pivotally held in the floor, preferably by a ball bearing construction,

2 and at its top end is pivotally mounted in a top support I as by the ball bearing l2. (See Fig. 3.) At the top of the door is the circular disk I3 which is concentric with the shaft and provides at its edge a braking track It. This disk is secured with the door and rotates with the door.

Mounted on a stationary structure near the door is a hydraulic cylinder l5 having the piston l6, and at the end of the piston is a brake shoe I which is adapted to frictionally engage the track M. A spring I8 extends between shoulder it on the piston and the brake shoe and is adapted to maintain the shoe resiliently in engagement with the track when the piston is advanced. Another spring l9 extends between the piston head l6 and the front end of the cylinder and is for the purpose of returning the piston to retracted position when hydraulic pressure is not applied to the rear of the piston head.

A pipe line 2|] connects with the interior of cylinder ii at a point rearward of the piston head l6". and at its other end this line connects with a hydraulic pump or actuator 2|. The interior area of pump 2| is centrally separated by the diaphragm 22, and hydraulic fluid is contained forward of this diaphragm. A piston 23 extends forwardly into the chamber and connects with the central portion of the diaphragm.

The electrical system, which is intended to control the hydraulic mechanism, includes a, battery 25 or other suitable source of electrical energy, a hand switch or circuit breaker 26 for safety purposes, a solenoid 21, and a switch 43 adapted to be operated by the governor in a manner to be explained later. The solenoid 21 is equipped with a plunger 29 which, when extended, contacts and urges forward the piston 33 of the actuator 2 I.

The governor G, more clearly illustrated in Figs. 2 and 3, includes a central shaft 30, which shaft may be an extension of the shaft Hi. The governor is disposed above the top stationary support, as seen in Fig. 3.

Slidably received over shaft 30 is a sleeve or body portion 3|. This body portion is adapted to slide vertically along the shaft and is pressed upwardly by the spring 32, which also extends about shaft 30 and is supported at its bottom by the nut 33 which is held secure by the lock nut 34. Above body 3| is a collar 35, which is locked to the shaft 30 by the set screw 36. This collar is provided with two or more pairs of arms 31. The present illustration shows four pairs of such arms. Pivotally mounted in each of these pairs of arms is a member 38 which is sensitive to cenq trifugal force. Weights 39 are carried at their lower ends. At the upper ends of these members are the fingers 40 which extend inwardly and contact the top ends of pins M. Pins 4| extend downwardly through openings in the collar 35 and are secured in the body 3| by means of the set screws 42. The auxiliary springs 43 may be employed, if desired, for aiding in holding the centrifugal membm's in retracted position.

At the upper end of shaft 30 is the collar member 44 which is slidably received on the shaft and adapted to move vertically thereon. This collar member is held in fixed relation to the body 3| by means of the pins 45 which are secured by set screws to both the collar member and the body member and which extend through openings in the collar 35. Collar member 44 is equipped with a flange 45 which extends over the button 41 of the electrical switch 48 mounted nearby on support 49.

As the governor is rotated more rapidly, the centrifugal members 38 will be caused to move about their pivots, permitting the balls 19 to swing outwardly. Their upper ends are then caused to press downwardly on the pins 4| causing the body 3! and also the member M to be moved downwardly. This brings the flange 56 into engagement with the button 41 on switch 48 so as to depress this button and maintain it depressed so long as the speed of the governor is such as to maintain the centrifugal members in their extended condition.

When the body 3| is depressed through the action of the centrifugal members, it be seen that it moves against spring 32 and it will be apparent that this spring maybe placed under greater tension, thereby causing operation of the governor only at greater rotational speeds by tightening the nut 83. Alternately, the governor maybe caused to operate at lesser speeds by turning down the nut 33 so as to loosen the spring.

With this improved arrangement, the revolving door may be mounted so as to be as nearly frictionless and move with as little effort as is possible. In operation, the door may revolve at low speeds with mere touch which is strong enough to overcome the natural momentum or the door. However, when through any circumstance, the door is accelerated to a certain speed for which the device is set, the centrifugal members 38 of the governor G swing outward to the point where the flange 46 of the governor depressed to the point where it presses the button B! of switch 48 to its down-wand position. This completes the electrical circuit, thus energizing the solenoid 21 and causing it to throw the plunger 29 forwardly. This pressure applied against the piston 23 presses the diaphragm 22 forwardly, thus urging iiuid through the line 20 and into cylinder l5 behind the piston H5. The piston l6 responds to this hydraulic pressure and moves forwardly, urging the brake shoe 4'! into frictional engagement with the track 14. Through the braking effect, due to this frictional engagement, the door is retarded in speed.

When the door comes to move more slowly and its speed is below the critical speed required for operation of the governor, the centrifugal members 38 will have moved inwardly sumcientiy to allow the body 3! of the governor "to rise urged by the spring 32, thus raising the flange &6 to the point where it no longer depresses button '41 of switch 48, and through the action of the springpressed button the electrical circuit is broken. This lie-energizes solenoid 21 releasing hydraulic pressure on the cylinder l5 and permitting the piston l6 to retract through the action of spring I9, thus removing the brake shoe H from frictional engagement with the track It.

Though I have described the structure of the illustrated embodiment in detail, it is to be understood that the operative elements may be designed in many different ways, and many specific constructions may be substituted for the one I have just described.

The foregoing detailed description has been given for purposes of explanation only and no unnecessary limitations are to be understood therefrom.

I claim:

1. A device for controlling the speed of a revolvmg door, comprising a governor connected with said door and arranged to rotate as said door revolves, braking means for checking the speed at which said door revolves, said braking means being normally in inoperative position, and power means independent of said door actuated by said governor when the governor has attained a, predetermined speed of rotation for moving said braking means into operative and for applying thereby a substantially constant braking force to the door so long as the speed of said door exceeds a predetermined value.

2. A device for controlling the speed of a revolving door, comprising a governor connected with said door and arranged to rotate as said door revolves, braking means including a hydraulic pressure system which is adapted to produce braking action when hydraulic pressure is applied to the system, and power means independent of said door actuated by said governor when the governor has attained -a predetermined speed of rotation for applying hydraulic pressure to said system and for applying thereby a substan-- tialiy constant braking force to the door so long as the speed of said. door exceeds a predeterminedvalue.

3. A device for controlling the speed of a revolving door, comprising a, governor connected with said door and arranged to rotate as said door revolves, braking means including a hydraulic pressure system which is adapted to produce braking action when hydraulic pressure is applied to the system, an electric circuit including means associated with said governor and adapted to sensitize the circuit when said governor attains a predetermined speed of rotation. and means for applying hydraulic pressure to said system when said circuit is sensitized to apply thereby a substantially constant braking force to the door so long as the speed of said door exceeds a predetermined value.

4. A device for controlling the speed of a revolving door, comprising a governor connected with said door and arranged to rotate as said door revolves, braking means for checking the speed at which said door revolves, said braking means being normally in inoperative position, an electric circuit including a source of electrical energy, switch means associated with said governor for altering the flow of current in said circuit when said governor has attained a predetermined speed and for maintaining said altered flow While said governor is rotating above said predetermined speed, hydraulic means for moving said braking means into operative position and for maintainlng it in operative position while hydraulic pressure is applied thereto, and means including a solenoid associated with said electric circuit for applying pressure to said hydraulic means when said current through said circuit is in said altered condition.

5. A device for controlling the speed of a revolving door, comprising means normally in nonoperating condition for applying a, constant pressure to retard the speed of revolution of said door, and a governor connected with said door and arranged to rotate as said door revolves, said governor having spring-held members which are impelled by centrifugal force to move against i spring tension as the speed of rotation of the governor increases, and means for conditioning said first-mentioned means for operation when said members have moved against spring tension to a predetermined position.

6. A device as set forth in claim 5 includin means for altering the spring tension of said members to thereby alter the speed of rotation of said governor at which said retarding means is changed to operative condition.

7. A device for controlling the speed of a revolving door, comprising a circular disk at the top of said door which is concentric with the axis of revolution of said door and the edge of which provides a friction surface, a brake shoe adapted to he moved into frictional contact with said edge, a hydraulic cylinder having a piston which is responsive to hydraulic pressure within the cylinder for pressing said shoe against said edge, said piston being provided with a spring for urging it 80 to withdrawn position so as to remove said shoe from frictional engagement with said edge when hydraulic pressure is not applied to said cylinder, means for applying hydraulic pressure to said cylinder, electrical means which when actuated is adapted to energize said pressure-applying means, and means associated with said door which is responsive to the speed of revolution of said door above a predetermined speed for actuating said electrical means.

8. A device for controlling the speed of a revolving door, comprising a governor connected with said door and arranged to rotate as said door revolves, braking means adapted when actuated to apply a constant and predetermined amount of pressure against the door to check the speed thereof, said braking means being normally in inoperative position, an electric circuit including means associated with said governor and adapted to sensitize the circuit when said governor attains a predetermined speed of rotation, and means for actuating said braking means to place the same in operative position when said circuit is sensitized.

LOUIS E. TELBIZOFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 871,509 Jordan Nov. 19, 190'? 1,947,733 Peremi Feb. 20, 1934 

